Unable to cancel schedule

We have multiple Asterisk boxes, all with exactly the same install… exactly the same. However the one box is deadlocking (not crashing) every few days - starting suddenly about a month ago. The log shows:

Then a few seconds or even minutes, later, you will notice that no new call setups work, and all the phones de-register.

About 10 minutes after that, poof, its all working again. I have seen VERY little on this (by googleing) but notice that at least one guy experienced the exact same thing.

Digging around, someone pointed to Grandstream (that has been a problem for us before).

This is Asterisk 1.8.21 - has anyone also experienced this, and does anyone have a clue what could actually cause this. It would make sense that the cause is from a new/rouge device, since clients sign up all the time some with their own equipment.

In the mean while i’m going to try 1.8.29 - but don’t see this issue int he changelog so cant say that its going to fix it.

Any feedback would help.

I have the same problem. Anybody have any idea?